Upstream Multiple Access Technology And Dynamic Bandwidth Allocation Model In Ethernet PON

While the demand of informational society for Internet services is dramatically increasing, access network has become a bottleneck between high-capacity local area networks and backbone networks. Ethernet Passive Optical Network (EPON), which is now a hot research topic in the network research field, is believed to be the best candidate for the next-generation access network. In this paper, we investigate the evolution of EPON upstream multiple access technology. In traditional TDMA, OLT allocates fixed time slot in Ethernet frame to each ONU. But the burst, self-similarity and long-range dependence of high-speed data traffic such as IP traffic will waste a considerable amount of network bandwidth and reduce the network performance. To improve the performance of the upstream multiple access, we design a new dynamic bandwidth allocation (DBA) algorithm. To support bandwidth allocation, Multipoint Control Protocol, which controls the operation of access with GRANT/REPORT mechanism, was developed in MAC Control layer. Our new DBA algorithm combining with GRANT/REPORT mechanism--Novel Polling algorithm can dynamically adjust transmission window size and decide the maximal size of the window. It is more efficient in utilizing the upstream bandwidth resources.In this paper, we also design a model on OPNET according to the basic EPON system. To analyze the performance of the model, we simulate and testify the effect of traffic bursts on the traditional TDMA system. Then, we modify the model with Novel Polling algorithm and analyze some network index such as end-to-end delay, queuing delay and throughput. The simulation show that the EPON model with Novel Polling algorithm performs better than that with other traditional algorithms based on the throughput, delay and fairness.